public async Task IsMemberAsync() { // Arrange var service = new ClanService(TestMock.ClanRepository.Object); TestMock.ClanRepository.Setup(repository => repository.IsMemberAsync(It.IsAny <UserId>())).ReturnsAsync(true).Verifiable(); // Act await service.IsMemberAsync(new UserId()); // Assert TestMock.ClanRepository.Verify(repository => repository.IsMemberAsync(It.IsAny <UserId>()), Times.Once); }